Nuclear Theory·nucl-th

Tuesday·December 12, 2017

21 papers—13 primary·8 cross-listed

14
[Submitted on 28 Aug 2017] (cross-list from hep-ph)
Electrodynamics of dual superconducting chiral medium
Yang Li🇺🇸 · Kirill Tuchin🇺🇸
We study the electrodynamics of a chiral medium with electric and magnetic charges using the effective Maxwell-Chern-Simons theory extended to include the magnetic current. The exchange of helicity between the chiral medium and the magnetic field, known as the inverse cascade, is controlled by the chiral anomaly equation. In the presence of the magnetic current, the magnetic helicity is dissipated, so that the inverse cascade stops when the magnetic helicity vanishes while the chiral conductivity reaches a non-vanishing stationary value satisfying $σ_{χ}^{2} < 4 σ_{e} σ_{m}$ , where $σ_{e}$ , $σ_{m}$ and $σ_{χ}$ are the electric, magnetic and chiral conductivities respectively. We argue that this state is superconducting and exhibits the Meissner effect for both electric and magnetic fields. Moreover, this state is stable with respect to small magnetic helicity fluctuations; the magnetic helicity becomes unstable only when the inequality mentioned above is violated.
Comments:
13 pages, 11 figures. To appear in Phys. Lett. B
Subjects:
High Energy Physics — Phenomenology (hep-ph); Superconductivity (cond-mat.supr-con); Nuclear Theory (nucl-th)
arXiv:
1708.08536 [pdf]
PLB(2018)·8 citations
15
[Submitted on 24 Nov 2017] (cross-list from astro-ph.SR)
Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations
N. Nishimura · T. Rauscher · R. Hirschi · A. St. J. Murphy · G. Cescutti · C. Travaglio
Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of $p$ nuclides. Such nuclei are produced during the explosion, in layers enriched with seed nuclei coming from prior strong $s$ processing. These seeds are transformed to proton-richer isotopes mainly by photodisintegration reactions. Several thousand trajectories from a 2D explosion model were used in a Monte Carlo approach. Temperature-dependent uncertainties were assigned individually to thousands of rates varied simultaneously in post-processing in an extended nuclear reaction network. The uncertainties in the final nuclear abundances originating from uncertainties in the astrophysical reaction rates were determined. In addition to the 35 classical $p$ nuclides, abundance uncertainties were also determined for the radioactive nuclides $^{92}$ Nb, $^{97, 98}$ Tc, $^{146}$ Sm, and for the abundance ratios $Y$ ( $^{92}$ Mo)/ $Y$ ( $^{94}$ Mo), $Y$ ( $^{92}$ Nb)/ $Y$ ( $^{92}$ Mo), $Y$ ( $^{97}$ Tc)/ $Y$ ( $^{98}$ Ru), $Y$ ( $^{98}$ Tc)/ $Y$ ( $^{98}$ Ru), and $Y$ ( $^{146}$ Sm)/ $Y$ ( $^{144}$ Sm), important for Galactic Chemical Evolution studies. Uncertainties found were generally lower than a factor of two, although most nucleosynthesis flows mainly involve predicted rates with larger uncertainties. The main contribution to the total uncertainties comes from a group of trajectories with high peak density originating from the interior of the exploding white dwarf. The distinction between low-density and high-density trajectories allows more general conclusions to be drawn, also applicable to other simulations of white dwarf explosions.
Comments:
8 pages, 10 figures, 2 tables, MNRAS; minor revisions to match published version
Subjects:
Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1711.09098 [pdf]
MNRAS(2018)·47 citations
16
[Submitted on 8 Dec 2017] (cross-list from hep-ph)
SU(3) Polyakov linear-sigma model: Magnetic properties of QCD matter in thermal and dense medium
Abdel Nasser Tawfik🇪🇬 · Abdel Magied Diab (Egyptian Ctr. Theor. Phys., Cairo and WLCAPP, Cairo)🇪🇬 · T. M. Hussein (Cairo U.)🇪🇬
The linear-sigma model, in which information about confining gluons is included through the Polyakov-loop potential (PLSM), is considered in order to perform a systematic study for various magnetic properties of QCD matter under extreme conditions of high temperatures and densities and finite magnetic field strengths. The introduction of magnetic field to the PLSM Lagrangian requires suitable utilization of Landau quantization, modification in the dispersion relations, and momentum-space dimension-reduction. We observed that increasing the magnetic field leads to filling-up lower Landau levels first and decreasing the number of occupied levels. We conclude that the population of Landau levels is most sensitive to the magnetic field and to the quark charges. The influences of finite magnetic field on the temperature dependence of chiral and deconfinement order-parameter(s) are studied. We present estimations for the magnetization, the magnetic susceptibility, the permeability and the catalysis properties of QCD matter as functions of temperature. The dependences of the resulting freezeout parameters, temperatures and baryon chemical potentials on the corresponding magnetic field strengths have been analyzed, as well. These calculations are compared with recent lattice QCD simulations, whenever available. We conclude that the QCD matter seems to have paramagnetic property at temperatures greater than the critical one. There is an evidence for weak diamagnetic property at low temperatures. Last but not least, we observe that the magnetic catalysis is inverse, namely the critical temperatures decrease with increasing the magnetic field.
Comments:
27 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1712.03264 [pdf]
J.Exp.Theor.Phys.(2018)·22 citations
17
[Submitted on 9 Dec 2017] (cross-list from hep-ph)
Heavy Quark Spin Symmetry Violating Hadronic Transitions of Higher Charmonia
Muhammad Naeem Anwar🇨🇳 · Yu Lu🇩🇪 · Bing-Song Zou🇨🇳
In heavy quarkonia, hadronic transitions serve as an enlightened probe for the structure and help to establish the understanding of light quark coupling with a heavy degree of freedom. Moreover, in recent years, hadronic transitions revealed remarkable discoveries to identify the new conventional heavy quarkonia and extracting useful information about the so called "XYZ" exotic states. In this contribution, we present our predictions for heavy quark spin symmetry (HQSS) breaking hadronic transitions of higher $S$ and $D$ wave vector charmonia based on our recently proposed model (inspired by Nambu-Jona-Lasinio (NJL) model) to create light meson(s) in heavy quarkonium transitions. We also suggest spectroscopic quantum numbers $(^{2 S + 1} L_{J})$ for several observed charmoniumlike states. Our analysis indicates that the $Y (4360)$ is most likely to be a $3 D$ dominant state.
Comments:
Proceedings of the talk presented at "XVII International Conference on Hadron Spectroscopy and Structure (Hadron2017)", 25-29 September 2017, Salamanca, Spain
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1712.03425 [pdf]
PoS(2018)·3 citations
18
[Submitted on 10 Dec 2017] (cross-list from hep-ph)
Frame dependence of form factors in light-front dynamics
Yang Li🇺🇸 · Pieter Maris🇺🇸 · James Vary🇺🇸
In light-front dynamics, form factors are traditionally computed with the "good current" $J^{+}$ within the Drell-Yan frame $q^{+} = 0$ . Due to truncations imposed in practical calculations, the from factor may acquire frame dependence, which is often neglected. In this work, we explore the form factors in more general frames, preserving the boost covariance. We find the frame dependence of the elastic form factors for mesons is small in basis light-front holography and related models with two-body Fock space truncation. We suggest to use the difference between form factor results from Drell-Yan frame and the "longitudinal frame" as a metric for the violation of the Lorentz symmetry due to Fock space truncation.
Comments:
13 pages, 21 figures. Submitted to Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1712.03467 [pdf]
PRD(2018)·27 citations
19
[Submitted on 11 Dec 2017] (cross-list from hep-ph)
The QCD Phase Diagram from Statistical Model Analysis
Francesco Becattini · Marcus Bleicher · Jan Steinheimer · Reinhard Stock
Ideally, the Statistical Hadronization Model (SHM) freeze-out curve should reveal the QCD parton-hadron phase transformation line in the ( $T$ , $μ_{B}$ ) plane. We discuss the effects of various final state interaction phenomena, like baryon-antibaryon annihilation, core-corona effects or QCD critical point formation, which shift or deform the SHM freezeout curve. In particular, we present a method to remove the annihilation effects by quantifying them with the microscopic hadron transport model UrQMD. We further discuss the new aspects of hadronization that could be associated with the relatively broad cross-over phase transformation as predicted by lattice-QCD theory at low $μ_{B}$ . That opens up the possibility that various observables of hadronization, e.g. hadron formation or susceptibilities of higher order (related to grand canonical fluctuations of conserved hadronic charges) may freeze out at different characteristic temperatures. This puts into question the concept of a universal \textit{(pseudo-)critical} temperature, as does the very nature of a cross-over phase transformation.
Comments:
24 pages, 11 figures. Submitted as part of the Walter Greiner memorial book
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1712.03748 [pdf]
7 citations
20
[Submitted on 11 Dec 2017] (cross-list from hep-ph)
Electrical and thermal conductivities of hot and dense hadron gas
Guruprasad Kadam🇮🇳 · Hiranmaya Mishra🇮🇳 · Lata Thakur🇮🇳
We estimate the electrical and thermal conductivities of hot and dense hadronic matter in the relaxation time approximation of the Boltzmann equation. We estimate the thermodynamical quantities of hot and dense hadronic matter within the ambit of the excluded volume hadron resonance gas model. The relaxation time for all the hadrons is estimated assuming the constant cross section with uniform as well as mass dependent hard-core radius. We compare our results with various existing results. Finally we give an estimate of electrical and thermal conductivities in the context of heavy ion collision experiments.
Comments:
18 pages, 5 figures, Added discussions, typos corrected, version to appear in Phys. Rev. D
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1712.03805 [pdf]
PRD(2018)·36 citations
21
[Submitted on 11 Dec 2017] (cross-list from hep-ph)
Sum rules across the unpolarized Compton processes involving generalized polarizabilities and moments of nucleon structure functions
Vadim Lensky🇩🇪 · Franziska Hagelstein🇨🇭 · Vladimir Pascalutsa🇩🇪 · Marc Vanderhaeghen🇩🇪
We derive two new sum rules for the unpolarized doubly virtual Compton scattering process on a nucleon, which establish novel low- $Q^{2}$ relations involving the nucleon's generalized polarizabilities and moments of the nucleon's unpolarized structure functions $F_{1} (x, Q^{2})$ and $F_{2} (x, Q^{2})$ . These relations facilitate the determination of some structure constants which can only be accessed in off-forward doubly virtual Compton scattering, not experimentally accessible at present. We perform an empirical determination for the proton and compare our results with a next-to-leading-order chiral perturbation theory prediction. We also show how these relations may be useful for a model-independent determination of the low- $Q^{2}$ subtraction function in the Compton amplitude, which enters the two-photon-exchange contribution to the Lamb shift of (muonic) hydrogen. An explicit calculation of the $Δ (1232)$ -resonance contribution to the muonic-hydrogen $2 P - 2 S$ Lamb shift yields $- 1 \pm 1$ $μ$ eV, confirming the previously conjectured smallness of this effect.
Comments:
22 pages, 5 figures, minor modifications, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1712.03886 [pdf]
PRD(2018)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE